1. Field of the Invention
The present invention relates to a diffusion plate and a diffusion plate assembly and particularly to a diffusion plate that has a plurality of bar-type patterns on an emission surface and a diffusion plate assembly including the diffusion plate.
2. Description of the Prior Art
In recent years, the traditional cathode ray tube display (commonly called CRT display) has been gradually replaced by a liquid crystal display (LCD). The main reason is that the LCD releases far less radiation than the CRT display. Moreover, the production cost of the LCD dropped significantly in the recent years. In general, the LCD includes a backlight module and a liquid crystal panel. The backlight module mainly aims to provide a light source for the LCD.
The backlight module generally includes a diffusion plate which contains multiple light diffusion particles made from a transparent polymer to diffuse light generated by cold cathode fluorescent lamps (CCFLs) to reduce impact on display quality resulting from illumination shade generated by the CCFLs. Without the diffusion plate, the display surface will have visible bright and dark strips. In the earlier time, the diffusion plate is a plane structure. As technology advances, the diffusion plate with patterns formed on the emission surface has been developed to further improve the display quality.
Refer to FIG. 1 for a conventional diffusion plate 100 which has a plurality of patterns 120 formed on an emission surface 110. When light 10 passes through the patterns 120, its travel direction changes, hence, reducing impact on display quality caused by the illumination shade generated by the CCFLs. The patterns 120 usually are formed in are shapes protruding outwards. Hence, light passing through the patterns 120 converges first at a focal point 120P before diffusing. As a result, its diffusion effect is not desirable.
How to make the diffusion plate to fully generate desired diffusion effect is an issue remained to be resolved in the industry.